Leaf springs are used in suspension systems for motor vehicles such as small utility vehicles, trucks, and the like. A pair of leaf springs can support a vehicle frame over an axle and absorb at least part of the vibrations experienced by the axle during traveling over rough rods. In addition, the leaf springs can provide a cost effective suspension for vehicles carrying heavy loads.
Leaf springs generally have a linear load deflection curve or spring rate and as such are not adjustable when the vehicle is subjected to different road conditions, cargo weights and the like. As such, a leaf spring suspension system can result in less than desired driver comfort when conditions such as road conditions and cargo weight fall outside of a range(s) used to “set up” the suspension system. Therefore, a suspension apparatus or system that uses leaf springs and affords adjustment of a leaf spring rate would be desirable.